Adding up Quaternion rotating around incorrect axis

Hi everyone,

I'm trying to rotate an object by multiplying 2 quaternions with each other. The issue is that when I would like to rotate it, it rotates in the wrong axis.



I've added a snippet of code and hope that someone would be able to help me with this issue.

Code (CSharp):

1.  
2.         public void UpdateTransform()
3.         {
4.             Vector3 desiredPosition = attachedMove.transform.position;
5.             Quaternion desiredRotation = attachedMove.transform.rotation;
6.  
7.             bool positionAltered = false;
8.             bool rotationAltered = false;
9.  
10.             while (movementQueue.Count > 0)
11.             {
12.                 positionAltered = true;
13.                 PositionSet translation = movementQueue.Dequeue();
14.  
15.                 if (translation.TranslationType == TranslationType.Additive)
16.                     desiredPosition += translation.Translation;
17.                 else if (translation.TranslationType == TranslationType.Override)
18.                     desiredPosition = translation.Translation;
19.             }
20.  
21.             while (rotationQueue.Count > 0)
22.             {
23.                 rotationAltered = true;
24.                 RotationSet rotation = rotationQueue.Dequeue();
25.  
26.                 Debug.Log("[Maarten] Adding Rotation: " + rotation.Rotation.eulerAngles + " | Old Rotation: " + desiredRotation.eulerAngles);
27.  
28.                 if (rotation.TranslationType == TranslationType.Additive)
29.                     desiredRotation *= rotation.Rotation; // This is executing.
30.                 else if (rotation.TranslationType == TranslationType.Override)
31.                     desiredRotation = rotation.Rotation;
32.  
33.                 Debug.Log("[Maarten] Current Rotation: " + desiredRotation.eulerAngles);
34.             }
35.  
36.             if (attachedMove.Rigidbody)
37.             {
38.                 if (positionAltered)
39.                     attachedMove.Rigidbody.MovePosition(desiredPosition); // This is also executing.
40.  
41.                 if (rotationAltered)
42.                     attachedMove.Rigidbody.MoveRotation(desiredRotation);
43.             }
44.             else
45.             {
46.                 if (positionAltered)
47.                     attachedMove.transform.position = desiredPosition;
48.  
49.                 if (rotationAltered)
50.                     attachedMove.transform.rotation = desiredRotation;
51.             }
52.         }
53.  
54.  

Thanks in advance!


- Maarten

 

When working with Quaterions, order matters. A * B != B * A

 

Yeah, that's what I read as well in another post and that's what I did as you can see in the code.

If I remember it correctly, A is the rotation base of the object and B is the rotation that should be added, right?

 

Sorry, just looked at your debug.log and it looks correct. Take the first one, if it is rotated globally 90 on the X and you add a small amount to its local Y axis, that will affect the global x.

 

Suppose that R is your current rotation and dY is a small rotation on the Y axis.

dY * R will slightly rotate around the global Y axis

R * dY will slightly rotate around your object's local Y axis (which could be anywhere, depending on your starting rotation R). Imagine that you were applying the rotation to a child object that was "inheriting" the rotation R from its parent and then using dY as its local rotation value.

 

Interesting. Will try that out tomorrow. Will keep you posted!

 

It's working. Great! Thanks a lot, guys!